1. Field of the Invention
The presenting invention relates to materials, detectors and systems for spectroscopic detection.
2. Background of the Related Art
The identification of chemical vapors requires both collection and analysis of the vapors. The collection technique must obtain the chemical vapor and provide the chemical in a form that is convenient for analysis. The analysis technique must be able to utilize the chemical and provide the desired identification information. For example, trace amounts of chemical warfare agents have been successfully detected using solid phase extraction (SPE) techniques followed by gas chromatography-mass spectrometry (GC-MS) analysis. However, this method is complicated, as it requires very sophisticated and expensive instrumentation and highly skilled operator to perform the test.
Optical spectroscopic methods such as infrared and Raman spectroscopy can provide unique spectral fingerprints of organic compounds, facilitating the unambiguous identification of chemical warfare agents (CWAs) and other toxic industrial chemicals. However, improved collections techniques are necessary before these analytical techniques can be used to full advantage.
While solid phase extraction substrates can be used to collect chemical vapors, substrates known to be capable of adsorbing chemical vapors are also known to interfere with spectroscopic detection. In other words, the solid phase extraction substrate that collects and concentrates organic vapors onto its surface is not “spectroscopically benign.” A substrate is spectroscopically benign if it either transmits or reflects electromagnetic radiation over a desired range of wavelengths.
Therefore, detecting trace concentrations of a chemical analyte, such as an organic vapor, remains a challenge and there is a need for more sensitive and selective chemical and biological sensor technologies. It would be desirable if a sensor could collect and analyze chemical analyte samples without extensive handling or processing of the sample. It would be further desirable if the sensor provided efficient collection and sensitive analysis to enable detection of even small amounts of an analyte. Still, it would be even more desirable if the sensor could identify or differentiate a chemical of interest from a mixture of other chemicals.